Design of Distributed Sparse Arrays for Lamb Wave SHM Based upon Estimated Scattering Matrices.

A common practice in guided wave structural health monitoring is collecting measurements from a transducer array using the pitch-catch method. Among different array configurations, the spatially distributed array provides a cost-effective solution for rapid interrogation of large, plate-like structures. Several guided wave imaging techniques have been proposed and successfully demonstrated for damage detection and localization. However, the performance of these imaging methods can be compromised by a mismatch between a particular transducer array geometry and the scattering characteristics of a defect of interest. This study proposes a method, which is based upon estimating scattering matrices, to quantify the ability of a specific array geometry to interrogate a scatterer. Several array geometries are evaluated using this method, and a Monte Carlo simulation is then performed to vary the transducer locations to find the array geometry that is best matched to a specific directional scatterer. The efficacy of the proposed method is evaluated experimentally by introducing notches of different orientations and locations on an aluminum plate specimen that is instrumented with a spatially distributed array. [ABSTRACT FROM AUTHOR]